Statistics reveal that in excess of three thousand persons suffer heat attacks each day. Over one thousand of these die. It has been clinically proved the quicker the right aid can be administered to the victim the better the chances for recovery. Of the one thousand plus who die each day, over one half could be saved by receiving effective treatment quickly enough to offset the damage done in the early stages of the attack. Also, of the two thousand or so who "survive", the severity of the damage, or impairment, could be reduced substantially by receiving effective treatment quickly enough. The immediate effect of an acute myocardial infarction which leads to fatality is ventricular fibrillation or VF. Ventricular fibrillation is amenable to treatment by electro-shock via a defibrillator, and this treatment is currently employed in hospital emergency areas and coronary care units, as well as by some emergency rescue units.
The complexities of operating this equipment, which, in some cases, requires interpretation of oscilloscope displays and the like greatly limit its use. In addition, the high cost of presently available equipment puts it beyond the financial reach of many in these groups. Consequently, many of the one million plus "heart" victims each year are outside the area of the quality assistance they need within the critical time they need it.
This number one killer and crippler of modern man effects those our society can least afford to lose. Too many of our leaders and/or executors in the religious, cultural, academic, professional, business, financial, and political areanas are struck down in their prime. The survivors, are severally penalized through the loss of their talents and possible contributions by their untimely demise.
The object of this invention is to provide self-monitoring, self-evaluating machines in great enough availability so that these victims can receive quality assistance within the critical framework of time to prevent either death or debilitating after effects.
The electrocardiogram waveform for a heart in the arrhythmic condition of ventricular fibrillation is unique in that it consists of completely unformed complexes-disorganized-irregular. In contrast, practically all the others have certain repetitive characteristics even though they may contain irregularities. From this, this invention is based on the fact that certain wave components will maintain a rather consistant amplitude; both those above the line-the P, R and T curves-and those below, the Q and S. Even when the pulse rate varies, a pattern repeat is discernible, sometimes after several pulse beats. According to this invention, the wave is sampled, analyzed for peaking repetitively within a preset amplitude variance, check these peaks in a selected time frame, compare the slope of a segment-say either the Q-R or the R-S in several beats over a monitoring period of some five to ten or so seconds to distinguish many similarities in all conditions except in ventricular fibrillation. Should at least a minimal number of similarities be detected in this period, it can quite safely be assumed the heart is not in ventricular fibrillation. Whereas in the case of mismatch where similarities might occur at random and then only in few instances, it could quite safely be assumed the heart is in ventricular fibrillation VF. This condition would activate the machine. The exception to this would be where the amplitude is minimal-ventricular standstill. In the "flatline" condition, an external pacer should take control to reestablish the pulse beat. The more severe shock as induced for ventricular fibrillation would not correct this condition.
The automatic defibrillator according to this invention includes conventional electrode or paddle means for application to a patient's chest, means for storing a plurality of known electrocardiogram waveform characteristics of various heart conditions, the electrodes are coupled to conventional ECG circuitry for producing an electrocardiogram waveform of the patient's heart and an electrical circuit is provided for comparing the electrocardiogram waveform of said patient against each stored characteristic.
A determination is made of the presence or absence of all stored electrocardiogram waveform characteristics of various heart conditions in the electrocardiogram of said patient and a defibrillator is activated to apply defibrillating electrical energy to said patient via the electrodes upon detecting the absence of all stored electrocardiogram waveform characteristics of various heart conditions in said patient's electrocardiogram.